PROJECT SUMMARY/ABSTRACT Dr. Chongyi Wei's long-term goal is to build a research career in HIV/AIDS prevention research among MSM in resource-limited settings, with a primary focus on developing and evaluating HIV prevention interventions among Chinese MSM. Dr. Wei's history as an individual who has been trained in Western behavioral and epidemiological sciences, yet who understands Chinese culture and languages as a Chinese citizen, places him in a strong position to help avert a dangerous rise in HIV infections among Chinese MSM. This K99/R00 application is therefore uniquely timed to contribute to a growing field of prevention science in China and to alter the trajectory of the HIV epidemic among MSM. During the K99 phase, Dr. Wei will focus on realizing several short-term training and research objectives. Training Objectives: 1) Advanced training in developing and evaluating HIV prevention interventions; 2) Gain expertise and experiences in sampling, recruiting, and retaining hidden populations in resource-limited settings for prevention research; and 3) Further develop skills in analyzing data from observational and longitudinal studies focused on MSM and HIV. Research Objectives: 1) Conduct formative research with Chinese MSM to explore barriers to utilizing HIV VCT services, benefits of getting tested, and attitudes and norms toward HIV testing; and 2) Conduct formative research for time-location sampling (TLS) among Chinese MSM. These objectives are instrumental to the successful advancement to the R00 phase which proposes to develop and implement a social marketing campaign promoting HIV VCT among Chinese MSM. HIV prevalence and incidence among MSM have increased dramatically in Chinese urban areas. MSM now account for over a third of new HIV infections in China. Unrecognized infections, due to a very low prevalence of HIV testing, may be one of the driving forces of ongoing HIV transmission among Chinese MSM. While HIV VCT is free in China, the barriers to their use by MSM are not well known. We hypothesize that the lack of culturally appropriate MSM-specific promotion of VCT coupled with social, cultural, and structural barriers have discouraged MSM from accessing VCT. The R00 study proposes to develop and pilot test a social marketing campaign promoting VCT among Chinese MSM at venues frequented by MSM in Nanjing, China. To measure the acceptability of the campaign and its effect on VCT uptake, a cohort of 506 MSM will be recruited through TLS at baseline and followed at 6- and 12-month using an Internet-based survey. Psychosocial and behavioral variables (e.g., perceived benefits and barriers, depression, internalized homophobia, social support, HIV- related stigma and discrimination, sexual risk behaviors, drug and alcohol use/abuse) will be assessed to identify predictors of successful and unsuccessful VCT uptake after the campaign. This will be the first intervention designed to increase VCT uptake among MSM in China, which will provide important insights with respect to the social and cultural considerations of such an intervention among a marginalized population in a resource-limited setting, the translation of such an intervention to other communities in Asia, and among other high-risk populations.